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Deferred Compensation - Additional information (Detail) - USD ($) shares in Millions | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2019 | Mar. 31, 2018 | Dec. 31, 2018
Investments And Employee Deferred Compensation Plan [Line Items] |  |  |
Deferred Equity Participation Plan, distributions to key executives, age | Age 62 (or the one-year anniversary of the date of the grant for participants over the age of 61 as of the grant date) or upon or after their actual retirement. |  |
Deferred Equity Participation Sub-plans, distributions to key executives, age | Age 65 |  |
Deferred Equity Participation Sub-plans, distributions requisite service description | we annually make awards under sub-plans of the DEPP for certain production staff, which generally provide for vesting and/or distributions no sooner than five years from the date of awards, although certain awards vest and/or distribute after the earlier of fifteen years or the participant reaching age 65. |  |
Deferred Equity Participation Plan (DEPP) [Member] |  |  |
Investments And Employee Deferred Compensation Plan [Line Items] |  |  |
Awards approved by committee, value | $ 10,100,000 | $ 11,500,000 |
Charge to compensation expenses related to awards | 2,000,000 | 1,900,000 |
Cash and equity awards with aggregate fair value vested and distributed to participants | 0 |  |
Unearned deferred compensation, value | $ 69,000,000 |  | $ 57,600,000
Unearned deferred compensation, shares | 2.9 |  | 2.7
Total intrinsic value of unvested equity based awards | $ 224,000,000 |  | $ 199,800,000
Deferred Cash Participation Plan (DCPP) [Member] |  |  |
Investments And Employee Deferred Compensation Plan [Line Items] |  |  |
Awards approved by committee, value | 2,400,000 | 5,600,000 |
Charge to compensation expenses related to awards | 1,100,000 | 800,000 |
Cash and equity awards with aggregate fair value vested and distributed to participants | 800,000 |  |
Deferred Equity Participation Plan Sub Plans [Member] |  |  |
Investments And Employee Deferred Compensation Plan [Line Items] |  |  |
Awards approved by committee, value | 2,600,000 | 900,000 |
Charge to compensation expenses related to awards | 500,000 | $ 500,000 |
Cash and equity awards with aggregate fair value vested and distributed to participants | $ 0 |  |

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- Definition Compensation approved by committee, value + References No definition available. + Details
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- Definition Deferred Equity Participation Plan, Distributions to Key Executives, Age + References No definition available. + Details
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- Definition Deferred equity participation sub plan distributions requisite service description. + References No definition available. + Details
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- Definition Deferred equity participation sub plan distributions to key executives age. + References No definition available. + Details
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- Definition Investments And Employee Deferred Compensation Plan [Line Items] + References No definition available. + Details
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- Definition Represents the expense recognized during the period arising from equity-based compensation arrangements (for example, shares of stock, unit, stock options or other equity instruments) with employees, directors and certain consultants qualifying for treatment as employees. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5047-113901 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.F) -URI http://asc.fasb.org/extlink&oid=115993241&loc=d3e301413-122809 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (h)(1)(i) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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- Definition Amount of accumulated difference between fair value of underlying shares on dates of exercise and exercise price on options exercised (or share units converted) into shares. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=109197908&loc=d3e5070-113901 + Details
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